An executable meta model for re-engineering of database schemas

A logical database schema, e.g. a relational one, is an implementation of a specification, e.g. an entity-relationship diagram. Upcoming new data models and the necessity of seamless integration of databases into application programs require a cost-effective method for mapping from one data model into the other. We present an approach where the mapping relationship is divided into three parts. The first part maps the input schema into a so-called meta model. The second part rearranges the intermediate representation, and the last part produces the schema in the target data model. A prototype has been implemented on top of a deductive object base manager for the mapping of relational schemas to entity-relationship diagrams. From this, a C++-based tool has been derived that will be part of a commercial CASE environment.